Exercise performance is impaired both at maximal and submaximal levels in persons with NIDDM, especially women, even in the absence of complications. One finding in particular was that VO2/work load was lower in NIDDM compared to control during exercise, a finding which in certain cardiorespiratory disease states has been interpreted to suggest impaired oxygen delivery. We propose to extend our studies of the VO2/work load relationship in NIDDM by measuring VO2 kinetics and heart rate kinetics (descriptors of cardiopulmonary responses to exercise) during bouts of constant load exercise on the bicycle ergometer. In addition, we will evaluate the effects of three months of exercise training on these parameters. Patients will include 10 premenopausal women with uncomplicated NIDDM, 10 weight and age matched nondiabetic women and 10 lean age matched nondiabetic women (to control for effects of obesity). Slowed VO2 kinetics with slowed heart rate kinetics would suggest an impairment in oxygen delivery in NIDDM. The importance of these studies is 1) to use measurements of the rate of rise in oxygen consumption and heart rate with exercise(oxygen uptake kinetics) to determine whether there is a difference between persons with NIDDM and controls in terms of the adequacy with which oxygen is supplied to exercising muscle, and 2) to further understand the effects of NIDDM on cardiovascular function during exercise both at baseline and after modification by exercise training.